Mal-PEG8-t-butyl ester is widely utilized in bioconjugation and chemical biology for modifying biomolecules. Its PEG spacer enhances solubility and reduces immunogenicity, making it ideal for creating stable conjugates in drug delivery systems. The t-butyl ester group provides a protective moiety that can be selectively removed under mild conditions, enabling controlled release or activation of the molecule. This compound is particularly valuable in synthesizing antibody-drug conjugates (ADCs) and peptide-based therapeutics, where precise modification and stability are crucial. Additionally, it is employed in surface functionalization of nanoparticles and biomaterials to improve biocompatibility and targeting efficiency.